This procurement specification covers alloy steel and corrosion and heat resistant steel free running metric nuts of the following types, styles and classes: (a) Types: Hex nut plain, standard height; Hex nut plain, shear height; Hex nut slotted, standard height; Hex nut slotted, shear height; (b) Styles: Washer face; Double chamfered; Castellated; (c) Classes: 516 MPa axial strength, min (shear height nuts); 600 MPa axial strength, min (shear height nuts) 860 MPa axial strength, min; 1000 MPa axial strength, min. Application: Primarily for fastening aerospace propulsion parts using metric fasteners where the minimum axial strengths of the classes specified in (c) are required. Slotted nuts are intended for use with cotterpins or other similar applicable locking devices.